JASMONIC ACID PROMOTES DIVISION OF FERN PROTOPLASTS, ELONGATION OF RHIZOIDS AND EARLY DEVELOPMENT OF GAMETOPHYTES

The effects of jasmonic acid (JA) on spore germination, early gametoph yte development and sporophytic protoplast culture of the fern Platyce rium bifurcatum (Cav.) C. Chr. were investigated. JA had no influence on spore germination and primary rhizoid initiation, but significantly promoted early gametophyte development, which was evident from the lo nger primary rhizoids as well as the higher number of rhizoids and cel ls per gametophyte. Jasmonic acid (1 mu M) also promoted the transitio n of gametophytes from a filamentous to a planar growth. Optimal prima ry rhizoid elongation and highest cell division activities in the game tophytes were observed at 0.01-1 mu M JA, while the highest number of rhizoids on gametophytes was obtained at 0.1-1 mu M JA. Jasmonic acid (0.01 mu M) also stimulated initial protoplast divisions. Except for t he experiment in which the effect of JA on germination was tested, JA concentrations exceeding 1 mu M did not promote cell elongation or cel l division but were instead inhibitory. On the basis of these findings , we propose that JA may be involved in early stages of P. bifurcatum development.